Device and method for cleaving optical fibers

ABSTRACT

An optical fiber cleaving device includes an auxiliary support section movably disposed on a base section independently from a blade section and a pusher section. The auxiliary support section can be selectively disposed at the operable position for supporting an unsheathed optical fiber in cooperation with a pair of clamp sections. The auxiliary support section is constituted by a thin plate member having fiber support faces locally located between the clamp sections at the operable position and a relief area formed adjacent to the fiber support faces. The fiber support faces come in contact with the portions of a local length of the unsheathed optical fiber extending between the clamp sections, the local length being located away from the fiber cleaving position, and the relief area is so arranged as to avoid the contact with a portion of a second local length of the unsheathed optical fiber, located at the fiber cleaving position. The cleaving device can provide highly accurate cleaving for optical fibers having different fiber structures without changing the preset conditions for the clamp sections.

DETAILED DESCRIPTION OF THE INVENTION

1. Technical Field of the Invention

the present invention relates to an optical fiber cleaving device and anoptical fiber cleaving method.

2. Background

In the optical fiber cleaving technology, there has been known acleaving device comprising a pair of clamp sections arranged maintaininga predetermined gap, a moving blade section capable of bringing the edgethereof to a fiber cleaving position defined between the clamp sections,and a moving pusher section capable of bringing the pushing facesthereof to the fiber cleaving position independently of the bladesection, which are arranged on a base section (see, e.g., a patentdocument 1, U.S. Pat. No. 5,395,025). In the cleaving process by usingthis cleaving device, first, the sheath of the optical fiber is, first,removed from an end thereof over a desired length to expose the fiber,and this unsheathed optical fiber is supported in a fixed manner on thepair of clamp sections so as to extend therebetween. In this state, theblade section is moved straight on the base section in a direction atright angles with the unsheathed optical fiber to score (scribe), byusing the edge thereof, the outer surface of the cladding at a targetpoint of the unsheathed optical fiber placed at the fiber cleavingposition nearly at right angles with the axis of the fiber. Then, theblade section is moved away from the fiber cleaving position, the pushersection is caused to swing on the base section such that the pushingfaces forcibly enter into the fiber cleaving position, and a pushingforce is exerted on the unsheathed optical fiber supported between theclamp sections from the side opposite to the score. Then, the tensilestress generates in the unsheathed optical fiber with the score as acenter, and the unsheathed optical fiber is cleaved and cut at thepredetermined portion.

The above-mentioned cleaving device and cleaving method have heretoforebeen widely used since they are capable of easily and reliably formingthe end surfaces at the cleaved surfaces of the unsheathed optical fiberhaving a core of a glass, suppressing incompleteness such asinclination, undulation and roughness to lie within allowable ranges.Here, to stably form mirror-like end surfaces at right angles on theunsheathed optical fiber, a relative positional relationship that isprecisely determined in advance must be maintained with high precisionbetween the unsheathed optical fiber supported between the clampsections and the edge of the blade section that moves passing throughthe fiber cleaving position. That is, the cleaving device must becapable of scribing the cladding of the optical fiber to be cleavedmaintaining a size that is necessary and sufficient (scribing depth,etc.) maintaining high accuracy and good reproduceability. Therefore,the cleaving device of this type usually has a constitution whichsecures the optical fiber of a particular fiber structure (materials ofcore and clad, diameters, etc.) in a state of maintaining an optimumpositional relationship between the clamp sections and the bladesection. There has been known the cleaving device dedicated to thespecial optical fibers, which permits the height of edge of the bladesection to be finely adjusted in the order of microns on the basesection.

There has further been proposed a cleaving device of the above typefeaturing a general applicability to deal with unsheathed optical fibersof a plurality of types having different outer diameters by producing anoptimum tensile stress relying upon the pushing action of the pushingsection after the cladding has been scribed (see, e.g., a patentdocument 2, JP Unexamined Patent Publication (Kokai) No. 6-294914). Inthis cleaving device, a pair of clamp sections disposed on the basesection are so constituted as to be selectively moved in the directionsof approaching each other and separating away from each other. Further,each clamp section is constituted by a clamp plate moving on the basesection and a holder plate detachably mounted on the clamp plate. Thegap between the clamp sections is adjusted to an optimum value dependingupon the outer diameter of the unsheathed optical fiber that is to becleaved. Upon replacing the holder plate by the one having an optimumwidth, cleaved surfaces (end surfaces of the unsheathed fiber) of a highquality can be formed on the unsheathed optical fibers of dissimilarouter diameters by optimizing the curvatures of deflection at the timeof cleavage by the pushing force. The cleaving device described in thepatent document 2 further has a holding plate for holding the unsheathedoptical fiber in a contacting manner on the side opposite to the edge ofthe blade section at the time of scribing the outer surface of thecladding of the unsheathed optical fiber.

SUMMARY

It is an object of the present invention to provide an optical fibercleaving device for cleaving an unsheathed optical fiber extendingbetween the clamp sections by scribing the surface thereof with the edgeof the blade section and then pushing it, wherein scores are easily andreliably imparted to the surfaces of the unsheathed fibers to a degreenecessary and sufficient for forming mirror-like end surfaces at rightangles at the ends of the optical fibers having different unsheathedfiber structures without changing the relative positional relationshipbetween the clamp sections and the blade section, excluding theprobability of a decrease in the life of the edge of the blade sectionand offering general applicability.

It is another object of the present invention to provide an opticalfiber cleaving method of cleaving an unsheathed optical fiber extendingbetween the clamp sections by scribing the surface thereof and thenpushing it, wherein scores are easily and reliably imparted to thesurfaces of the unsheathed fibers to a degree necessary and sufficientfor forming mirror-like end surfaces at right angles at the ends of theoptical fibers having different unsheathed fiber structures withoutchanging the gap between the clamp sections.

In order to accomplish the above object, the invention as set forthherein provides an optical fiber cleaving device comprising a basesection, a pair of clamp sections provided on said base section andspaced at a predetermined distance from each other for supporting anunsheathed optical fiber extending therebetween, a blade sectionprovided movably relative to said base section and including an edgecapable of being disposed at a fiber cleaving position defined betweensaid clamp sections, and a pusher section provided movably relative tosaid base section independently of said blade section and including apushing face capable of being disposed at said fiber cleaving position,wherein said optical fiber cleaving device comprises an auxiliarysupport section provided movably relative to said base sectionindependently of said blade section and said pusher section, and capableof being disposed at an operable position for supporting an unsheathedoptical fiber in cooperation with said clamp sections; and that saidauxiliary support section includes a fiber support face locally locatedbetween said clamp sections at said operable position, said fibersupport face being so arranged as to come in contact with a local lengthof an unsheathed optical fiber extending between said clamp sections,the local length being located away from said fiber cleaving position.

An invention as set forth herein provides the optical fiber cleavingdevice of that described above, wherein said auxiliary support sectioncomprises a thin plate member including said fiber support face, arelief area formed adjacent to said fiber support face so as to be freeof contact with a second local length of said unsheathed optical fiberlocated at said fiber cleaving position, and a holdable area formedadjacent to said fiber support face so as to be supported by said clampsections together with said unsheathed optical fiber.

An invention as set forth herein provides the optical fiber cleavingdevice of that described above, further comprising a fiber holderdetachably mounted on said base for holding an optical fiber to becleaved, said thin plate member being attached to said fiber holder.

An invention as set forth herein provides the optical fiber cleavingdevice of that described above, further comprising a cover sectioncoupled to said base section in an openable/closable manner, whereinsaid auxiliary support section comprises a piece member movably attachedto said cover section and including said fiber support face in one endface thereof.

An invention as set forth herein provides the optical fiber cleavingdevice of that described above, further comprising a cover sectioncoupled to said base section in an openable/closable manner, whereinsaid auxiliary support section comprises a disc member rotatablyattached to said cover section and including said fiber support face inan outer peripheral surface thereof.

An invention as set forth in herein provides the optical fiber cleavingdevice of that described above, wherein said disk member is provided insaid outer peripheral surface with a plurality of fiber support faceshaving different sizes in a rotation-axis direction and an inoperableface arranged to be deviated toward a rotation center relative to saidfiber support faces.

An invention as set forth in herein provides a method for cleavingoptical fibers, wherein the method comprises providing a pair of clampsections capable of respectively supporting an unsheathed optical fiber,and spacing said clamp sections at a predetermined distance from eachother; providing an auxiliary support member including a fiber supportface capable of supporting an unsheathed optical fiber in cooperationwith said clamp sections; supporting an unsheathed optical fiber on saidclamp sections so as to extend between said clamp sections; securelyarranging said auxiliary support member relative to said clamp sectionsin a manner that said fiber support face come in contact with a firstlocal length of said unsheathed optical fiber extending between saidclamp sections; locally scribing a surface of a target point in a secondlocal length of said unsheathed optical fiber, adjacent to said firstlocal length, between said clamp sections in a direction generallyperpendicular to an axis of said unsheathed optical fiber; and applyinga pushing force to said second local length of said unsheathed opticalfiber in a radial direction between said clamp sections, so as to cleavesaid unsheathed optical fiber at said target point.

In recent years, there has been developed an optical fiber equipped witha permanent resin coating (which cannot be easily removed) to protectthe outer surface of the cladding of the unsheathed fiber. Theprotective coating works to protect the outer surface of the claddingfrom the scars due to rubbing and scratches at the time of removing thesheath of the optical fiber or at the time of subsequent cleaving of theoptical fiber. When it is attempted to cleave the optical fiber providedwith the protective coating by using the above-mentioned conventionalcleaving device, however, the cladding of the optical fiber is notscribed to a required depth by the edge of the blade section due to thepresence of the protective coating.

In the field of optical fibers nowadays, standard sizes have beenspecified concerning the outer diameters of the unsheathed fibers, andeven the optical fibers with the protective coating have been soproduced that the outer diameters of the unsheathed fibers inclusive ofthe protective coating comply with the standard sizes. When compared onthe basis of the same standard sizes, therefore, the optical fibers withthe protective coating possess outer diameters of the claddings whichare smaller than those of the optical fibers without the protectivecoating and, hence, the rigidity slightly decreases correspondingly. Ifthe cleaving device disclosed, for example, in the above patent document1 is used for the optical fibers of different kinds having the samestandard sizes, the cleaving device having a positional relationshipbetween the clamp sections and the blade section determined in advanceexclusively for the optical fibers of particular standard sizes, then,different scribing actions are imparted by the blade section. Concretelyspeaking, if it is attempted to cleave the optical fiber with theprotective coating by using the cleaving device that has been designedfor the optical fibers without protecting coating, the latter unsheathedoptical fiber supported on the clamp sections to extend therebetweenpresents its hard protective coating that can be scored little to theedge of the blade section when the edge of the blade section is broughtinto contact with the surface thereof, whereby the unsheathed fiberslightly slides relative to the clamp sections and is easily deflected.As a result, the distance between the cladding and the edge is expandedby a thickness of the protective coating, making it further difficult toscribe the cladding by a necessary amount by the edge.

In order for the edge of the blade section to reliably penetrate throughthe hard protective coating of the unsheathed optical fiber extendingbetween the clamp sections, it is recommended to decrease the gapbetween the clamp sections that serve as fixed fulcrums for theunsheathed fiber thereby to effectively increase the cutting loadexerted on the protective coating from the edge (the load varies inreverse proportion to the third power of the distance between thefulcrums). Even in the cleaving device exclusively for the opticalfibers of particular standard sizes, it can be contrived to adjust thegap between the clamp sections depending upon the kind of the opticalfiber (e.g., whether it has the protective coating). In this case,however, it becomes necessary to accurately adjust the amount ofdeflection of the unsheathed optical fiber as desired at the time ofscribing by using the edge. With the clamp gap-adjusting mechanism inthe cleaving device as disclosed in the above patent document 2,however, it is estimated that a high degree of adjustment technology isrequired by the operators and, besides, highly accurate clampguiding/positioning mechanism is required, deteriorating the yielddepending on the skill of the operators, causing the structure of thecleaving device to become complex, driving up the cost, and requiringcumbersome maintenance work. In particular, it is required to performthe high-precision work of adjusting a clamp-distance whenever the typesof optical fibers to be cleaved are changed, and as a result, labor andtime will be consumed for the fiber cleaving operation.

The cleaving device of the above patent document 2 is further providedwith the clamp gap-adjusting mechanism to optimize the curvature ofdeflection at the time when the unsheathed optical fibers havingdissimilar outer diameters are to be cleaved by the pushing force. Thedeflection of the unsheathed fiber at the time when it is scribed by theblade section is directly and forcibly cancelled by bringing the holdingplate that is separately disposed into contact with the scribed portionof the unsheathed fiber on the opposite side. With this constitution, anexcess of frictional load is exerted on the edge of the blade sectionfor every scribing operation, and the life of the edge may be shortened.

As another method of increasing the cleaving load that is given to theprotective coating of the unsheathed optical fiber from the edge of theblade section, there can be contrived to increase the height of edgerelative to the clamp sections (the load varies in proportion to thedisplacement). However, the mechanism for adjusting the height of edgeof the blade section provided for the conventional cleaving device isprovided for mainly a fine adjustment of the height, usually, in a unitof microns. In cleaving the optical fiber with the protective coating byusing the cleaving device designed for the optical fibers withoutprotective coating, therefore, even if the height of the edge is set toa maximum value by using the height adjustment mechanism, the edge isfar from penetrating through the protective coating, and the cladding isnot scribed to a required depth. Conversely, if the mechanism isstructured to be capable of increasing the height of the edge so as toachieve an increased cleaving load that is required, the unsheathedfiber may be excessively bent during the scribing operation at thehighest position, and the core and cladding may be damaged. Further, theedge height-adjusting mechanism itself involves such problems asdecreasing the yield depending upon the skill of the workers, causingthe structure of the cleaving device to become complex, driving up thecost, requiring cumbersome maintenance operation, etc.

It is estimated that the above problems appear conspicuously even whenit is attempted to cleave, by using a single cleaving device, not onlythe optical fibers having different fiber structures such as having orwithout having protective coating but also the optical fibers of fiberstructures having cores and claddings of different materials (quartzcore/quartz cladding, quartz core/resin cladding, multi-component glasscore/multi-component glass cladding, etc.).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating an optical fiber cleavingdevice according to a first embodiment of the present invention in astate of being used.

FIG. 2 is a view schematically illustrating a major portion of theoptical fiber cleaving device of FIG. 1.

FIG. 3 is a view schematically illustrating the major portion of theoptical fiber cleaving device of FIG. 1, wherein (a) is a viewillustrating the scribing operation by an edge, and (b) is a viewillustrating the pushing operation by a pusher section.

FIG. 4 is a sectional view of an optical fiber for which the opticalfiber cleaving device of FIG. 1 can be used, wherein (a) illustrates astructure without the protective coating, and (b) illustrates astructure with the protective coating.

FIG. 5 is a perspective view of an auxiliary support section with whichthe optical fiber cleaving device of FIG. 1 is provided.

FIG. 6 is a perspective view illustrating, on an enlarged scale, theauxiliary support section in the optical fiber cleaving device.

FIG. 7 is a view illustrating the operation of the auxiliary supportsection in the optical fiber cleaving device of FIG. 1, wherein (a)illustrates the scribing operation by the blade section of when theauxiliary support section is at the inoperable position, (b) illustratesthe scribing operation by the blade section of when the auxiliarysupport section is at the operable position, and (c) illustrates thepushing operation by the pusher section of when the auxiliary supportsection is at the operable position.

FIG. 8 is a perspective view illustrating the optical fiber cleavingdevice of FIG. 1 of when it is used in another way.

FIG. 9 is a view illustrating, on an enlarged scale, a clamping sectionin the optical fiber cleaving device of FIG. 1.

FIG. 10 is a perspective view illustrating a modified example of theauxiliary support section.

FIG. 11 is a perspective view illustrating another modified example ofthe auxiliary support section.

FIG. 12 is a perspective view illustrating a further modified example ofthe auxiliary support section.

FIG. 13 is a view illustrating the operation of the auxiliary supportsection of FIG. 12.

FIG. 14 is a view illustrating various examples of the auxiliary supportsection, wherein (a) is a plan view, (b) is a sectional view along theline B-B, (c) is a plan view, (d) is a sectional view along the lineD-D, (e) is a plan view, and (f) is a sectional view along the line F-F.

FIG. 15 is a perspective view illustrating a still further modifiedexample of the auxiliary support section, wherein (a) illustrates afiber holder at the open position, and (b) illustrates the fiber holderat the closed position.

FIG. 16 is a perspective view of the optical fiber cleaving deviceaccording to a second embodiment of the present invention.

FIG. 17 is a perspective view of the auxiliary support section withwhich the is optical fiber cleaving device of FIG. 16 is provided.

FIG. 18 is a view illustrating the operation of the auxiliary supportsection in the optical fiber cleaving device of FIG. 16, wherein (a) isa partial perspective view on an enlarged scale of when the auxiliarysupport section is at the inoperable position, and (b) is a viewillustrating the scribing operation by the blade section of when theauxiliary support section is at the inoperable position.

FIG. 19 is a view illustrating the operation of the auxiliary supportsection in the optical fiber cleaving device of FIG. 16, wherein (a) isa partial perspective view on an enlarged scale of when the auxiliarysupport section is at the operable position, and (b) is a viewillustrating the scribing operation by the blade section of when theauxiliary support section is at the operable position.

FIG. 20 is a perspective view of the optical fiber cleaving deviceaccording to a third embodiment of the present invention.

FIG. 21 is a perspective view illustrating on an enlarged scale theauxiliary support section in the optical fiber cleaving device of FIG.20.

FIG. 22 is a perspective view of the auxiliary support section withwhich the optical fiber cleaving device of FIG. 20 is provided.

FIG. 23 is a view illustrating the operation of the auxiliary supportsection in the optical fiber cleaving device of FIG. 20, wherein (a)illustrates the scribing operation by the blade section of when theauxiliary support section is at the inoperable position, and (b)illustrates the scribing operation by the blade section of when theauxiliary support section is at the operable position.

DETAILED DESCRIPTION

An embodiment of the present invention will now be described in detailwith reference to the accompanying drawings. In all of the drawings, thecorresponding constituent elements are denoted by common referencenumerals.

FIG. 1 is a view illustrating an optical fiber cleaving device 10according to a first embodiment of the present invention, FIGS. 2 and 3are views illustrating the constitution and action of major portions inthe optical fiber cleaving device 10, FIG. 4 is a view illustrating thestructure of an optical fiber to which the optical fiber cleaving device10 can be applied, and FIGS. 5 to 9 are views illustrating theconstitution and action of an auxiliary support section provided for theoptical fiber cleaving device 10.

Referring to FIGS. 1 to 3, the optical fiber cleaving device 10comprises a base section 12, a pair of clamp sections 14 secured on thebase section 12 maintaining a predetermined gap relative to each other,a blade section 16 disposed on the base section 12 so as to move, and apusher section 18 disposed on the base section 12 independently of theblade section 16 so as to move. The base section 12 is a rigid block ofnearly a rectangular shape as viewed on a plane, and has a first baseplate 20 and a second base plate 22 secured maintaining a gap relativeto each other on the surface thereof (upper surface in the drawing)defining a horizontal plane that serves as a reference for the fibercleaving operation. The first base plate 20 has a recessed portion 20 aformed in the top surface thereof at a predetermined position andextending in a horizontal direction. In the recessed portion 20 a isdetachably mounted a fiber holder 24 for holding an optical fiber F thatis to be cleaved at a predetermined position. The first plate 20 definesthe position of one clamp section 14 on the base section 12, and thesecond base plate 22 defines the position of the other clamp section 14on the base section 12. The clamp sections 14 are aligned on the basesection 12 in a direction in which the recessed portion 20 a extends,and are arranged on the same height.

The fiber holder 24 includes a rectangular and flat main body 26 thatwill be received by the recessed portion 20 a of the first base section20, and a rectangular and flat holder plate 28 rotatably coupled to oneedge that extends in the lengthwise direction of the main body 26. Inthe surface of the main body 26 is provided a holding groove (not shown)capable of positioning and holding an optical fiber F of a predeterminedsize, and the holder plate 28 turns relative to the main body 26 to openand close the holding groove. The fiber holder 24 firmly holds theoptical fiber F held in the holding groove in a state where the holderplate 28 is overlapped on the main body 26, and is, in this state,mounted on the recessed portion 20 a of the first base plate 20 suchthat the optical fiber F is positioned at a predetermined position onthe base section 12. As will be described later, the optical fiber F hasits sheath removed over a desired length from an end thereof in apreparatory stage in the optical fiber cleaving process, whereby theunsheathed optical fiber U is exposed. The optical fiber F is held bythe fiber holder 24 in a state where the unsheathed optical fiber U isextending outward.

The optical fiber cleaving device 10 further has a cover section 30coupled to the base section 12 so as to be opened and closed. The coversection 30 is a rigid plate of nearly a rectangular shape as viewed on aplane, and is rotatably supported by the first base plate 20 on the basesection 12 via a hinge 32 provided at an edge thereof. The pair of clampsections 14 include a pair of first clamp members 34 secured to the basesection 12 and a pair of second clamp members 36 secured to the coversection 30. The first clamp members 34 are secured to the first baseplate 20 and to the second base plate 22 on the base section 12 toconstitute local rectangular protuberances, respectively. On the otherhand, the second clamp members 36 are secured onto the cover section 30at positions where they are abut to the first clamp members 34 tosimilarly constitute local rectangular protuberances. In the coversection 30 is formed a notch 38 penetrating in the direction ofthickness of the plate between the second clamp members 36 and openingat the edge on the side opposite to the hinge 32.

The first clamp members 34 and the second clamp members 36 of the clampsections 14 have nearly flat clamp surfaces 34 a and 36 a at theirprotruded ends. The clamp surfaces 34 a, 36 a have such a shape thatthey are abut together in an intimately contacted manner when the coversection 30 is at a closed position covering the upper side of the basesection 12. Desirably, the clamp surfaces 34 a and 36 a are formed byelastic pieces 40 such as of a rubber attached to the clamp members 34,36. The clamp surfaces 34 a of the first clamp members 34 are arrangedon the same imaginary horizontal plane on the base section 12. Further,the clamp surfaces 36 a of the second clamp members 36 are arranged onthe same imaginary plane on the cover section 30, and, hence, come intosurface contact with all of the clamp surfaces 34 a of the first clampmembers 34 simultaneously accompanying the closing operation of thecover section 30. Owing to the above constitution of the clamp sections14, the unsheathed fiber U of the optical fiber F is supported betweenthe pair of clamp sections 14 at a predetermined height on the basesection 12 correctly extending in the horizontal direction at the timeof effecting the optical fiber cleaving process.

The blade section 16 has a disk-like shape with a center axis 16 a, andis forming a sharp arcuate edge 42 of, for example, a super hardmaterial along the outer circumferential edge thereof. The blade section16 is firmly supported by a moving plate 44 received in space betweenthe first base plate 20 and the second base plate 22 on the base section12 in such a manner that the edge 42 is exposed to a predeterminedheight. The moving plate 44 is mounted on the base section 12 so as tolinearly reciprocate via a linear guide 46 in a horizontal direction Sat right angles with the unsheathed optical fiber U extending betweenthe clamp sections 14. The blade section 16 has its edge 42 arranged inparallel with the direction S in which the moving plate 44 moves,whereby the edge 42 is arranged at a fiber cleaving position P definedbetween the clamp sections 14 (nearly at the center in the drawing).Namely, the fiber cleaving position P is defined within a linearlymoving passage of the edge 42.

At the optical fiber cleaving process, the blade section 16 iscontinuously moved by, for example, hand on the base section 12 in ahorizontal direction from the initial position shown in FIG. 2 toapproach the unsheathed optical fiber U supported by the clamp sections14. At a moment when the edge 42 of the blade section 16 passes throughthe fiber cleaving position P, the outer surface of the cladding of theunsheathed fiber U is scored (scribed) in a direction nearly at rightangles with the axis of the unsheathed fiber U (FIG. 3( a)). Next, theblade section 16 is disposed separated away from the unsheathed fiber Uon the side opposite to the initial position. In this state, the fiberpushing (cleaving) operation is effected by the pusher section 18.Thereafter, the blade section 16 is returned to the initial position towait for the next optical fiber cleaving process. The blade section 16can be turned about the axis 16 a to renew the edge 42. Further, theremay be provided an edge height-adjusting mechanism, that is not shown,in order to finely adjust the height of the edge 42 in a unit of micronsrelative to the clamp surfaces 34 a of the first clamp members 34 of theclamp sections 4 on the base section 12.

The pusher section 18 assumes the form of a swing arm with a rotary axisand has a nearly flat pushing face 48 at its free end facing in therotational direction. The pusher section 18 is rotatably supported atits base end by a pivot plate 50 provided on the first base plate 20 ofthe base section 12. The pivot plate 50 is secured to an end of amounting arm 52 disposed on the first base plate 20 along the edge onthe side opposite to the hinge 32 of the cover section 30, and isarranged being spaced part over the moving passage of the moving plate44 on the base section 12. The pusher section 18 has its axis ofrotation in parallel with the center axis 16 a of the blade section 16,whereby the pushing face 48 is disposed at the fiber cleaving position Pdefined between the clamp sections 14. Namely, the fiber cleavingposition P is defined within an arcuate moving passage of the pushingface 48. The swing arm of the pusher section 18 has such a size that canbe received in a non-contacting manner by the notch 38 in the coversection 30 that is at the closed position on the base section 12. Also,in place of the illustrated structure, the pusher section 18 may beinstalled on the cover section 30, or the pusher section 18 may beinterlocked with the blade section 16 or the cover section 30.

In the optical fiber cleaving process, after the operation for scribingthe unsheathed fiber by the blade section 16, the pusher section 18 iscaused to swing by, for example, hand in a direction to approach theunsheathed optical fiber U supported by the clamp sections 14 from theinitial position shown in FIG. 1 on the base section 12. Then, thepushing face 48 of the pusher section 18 arrives at the fiber cleavingposition P, and a pushing force f due to human hand is exerted on theouter surface of the cladding of the unsheathed fiber U in a directionnearly at right angles with the axis of the unsheathed fiber U on theside opposite to the score formed by the blade section. Therefore,tensile stress generates in the unsheathed optical fiber U with thescore as a center, and the unsheathed optical fiber U is cleaved and cutat a target point to thereby form an end surface B (FIG. 3( b)). Afterthe end of the optical fiber cleaving process, the pusher unit 18 isreturned back to the initial position and waits for the next opticalfiber cleaving process. A slot may be formed in the pushing face 48 ofthe pusher section 18, to avoid collision with the edge 42 of the bladesection 16 due to careless operation, and also to prevent the cut endsurface E of the unsheathed optical fiber U from being polluted.

The optical fiber F that can be cleaved by the optical fiber cleavingdevice 10 is the one obtained by, as shown in FIG. 4( a), covering, witha resin sheath S, the unsheathed fiber U comprising a core C1 and acladding C2, at least the core C1 being formed of quartz or amulti-component glass. In the optical fiber cleaving device 10, arelative positional relationship between the clamp sections 14 and theblade section 16 has been set in advance depending upon the outerdiameter (e.g., international standard size) of the unsheathed opticalfiber, so that a mirror-like end surface E can be formed at right angleson the optical fiber F at the cleaved end of the unsheathed fiber U. Theoptical fiber cleaving device 10 has been so constituted as to form amirror-like end surface E at right angles at the cut end of theunsheathed fiber U′ even for the optical fiber FIG. 4( b)) containingthe unsheathed fiber U′ having the same outer diameter as the outerdiameter of the unsheathed fiber U but having a permanent resinprotective coating C3 (that cannot be easily removed) for protecting theouter surface of the cladding C2 at the time of removing the sheath S,without the need of changing the positional relationship between theclamp sections 14 and the blade section 16.

Namely, the optical fiber cleaving device 10, further, has the auxiliarysupport section 54 disposed to move relative to the base section 12independently of the blade section 16 and the pusher section 18,constituting a feature of the invention. The auxiliary support section54 can be disposed at an operable position on the base section 12. Atthis operable position, the unsheathed optical fiber U′ having theprotective coating C3 is supported in cooperation with the clampsections 14. The optical fiber cleaving device 10 effects the cleavingprocess for the unsheathed optical fibers U, U′ of different kindshaving the same outer diameter by suitably moving the auxiliary supportsection 54 between the operable position and the inoperable position tothereby highly accurately cleave the unsheathed optical fibers U, U′.

In the illustrated embodiment, the auxiliary support section 54 isconstituted by a thin plate member 56 formed by using a thin platemember inclusive of a sheet, a film, a foil or the like in apredetermined profile. Referring to FIG. 5, the thin plate member 56 hasa pair of fiber support faces 58 that are separated on predeterminedregions on one surface thereof, the pair of fiber support faces 58locally located between the clamp sections 14 at the operable positionof the auxiliary support section 54. When the thin plate member 56 is atthe operable position, the fiber support faces 58 are so arranged as tocome in contact with a pair of first local lengths L1 (see FIG. 7) ofthe unsheathed optical fiber U′ supported to extend between the clampsections 14, the first local lengths being located away from the fibercleaving position P.

The thin plate member 56 further has a relief area 60 which is a throughhole formed between the fiber support faces 58 adjacent thereto, and apair of holdable areas 62 formed on the outer side of the two fibersupport faces 58 adjacent thereto. When the thin plate 56 is at theoperable position, the relief area 60 works to avoid the contact with asecond local length L2 (see FIG. 7) of the unsheathed optical fiber U′,located to extend through the fiber cleaving position P. When the thinplate member 56 is at the acting position, further, the pair of holdableareas 62 are supported by the clamp sections 14 together with theunsheathed optical fiber U′.

The thin plate member 56 further has a mounting hole 64 penetrating inthe direction of thickness of the plate in an end region extendingtoward the outer side of one holdable area 62. The mounting hole 64slidably receives a support pole 66 protruded at a desired position ofthe cover section 30 (near one second clamp member 36 in the drawing),whereby the thin plate member 56 is mounted on the cover section 30 soas to rotate in a direction in parallel with the fiber support faces 58with the support pole 66 as a center. In the support pole 66 of thecover section 30, there can be formed a circumferential groove (notshown) for detachably fitting an edge of the mounting hole 64 of thethin plate member 56 at nearly the same height as the clamp surface 36 aof the second clamp member 36 on the cover section 30. Further, the thinplate member 56 can be mounted on, for example, the second base plate 22of the base section 12 instead of on the cover section 30.

Operation of the auxiliary support section 54 having the above thinplate member 56 will now be described with reference to FIGS. 7 and 8.

The thin plate member 56 constituting the auxiliary support section 54is placed at the inoperable position on the cover section 30 shown inFIG. 1 when the above-mentioned cleaving process (FIG. 3) is effectedfor the optical fiber F without the protective coating. When it isattempted to effect the same cleaving process for the optical fiber F′with the protective coating in a state where the thin plate member 56 isat the operable position, the unsheathed optical fiber U′ supported onthe pair of clamp sections 14 so as to extend therebetween has its hardprotective coating C3 that is little likely to be scribed pushed againstthe edge 42, whereby the unsheathed fiber U′ itself slides slightly withrespect to the clamp sections 14 and is easily deflected (arrows a)(FIG. 7( a)). As a result, it becomes difficult to have the cladding C2scribed to a degree necessary and sufficient by the edge 42 compoundedby the fact that the distance between the cladding C2 and the edge 42has been increased by a thickness of the protective coating C3 (FIG. 4).

When the cleaving process is to be effected for the optical fiber F′,therefore, the thin plate member 56 is turned on the cover section 30from the inoperable position shown in FIG. 1 with the support pole 66 asa center, such that the pair of holdable areas 62 are overlapped on thepair of second clamp members 36 (FIG. 8). In this state, the coversection 30 is moved to a closed position relative to the base section12, whereby the thin plate member 56 is disposed at the operableposition, and the unsheathed optical fiber U′ positioned at apredetermined place on the base section 12 by the fiber holder 24, issupported so as to extend between the two clamp sections 14 with thethin plate member 56 being interposed between the unsheathed opticalfiber U′ and the second clamp sections 36 (FIG. 7( b)). At this operableposition, the pair of holdable areas 62 of the thin plate member 56 areheld between the unsheathed optical fiber U′ and the clamp faces 36 a ofthe second clamp members 36, and the fiber support faces 58 come incontact with the local lengths L1 of the unsheathed optical fiber U′,adjacent to the clamp sections 14.

In this state, the blade section 16 is so moved from the initialposition (FIG. 2) that the edge 42 thereof is brought into contact withthe surface of the unsheathed optical fiber U′. Then, the two fibersupport faces 58 of the thin plate member 56 work as fulcrums forsecuring the unsheathed optical fiber U′ in one direction receiving, atan upper side, the contacting force of the edge 42 from the lower side.Therefore, there is exhibited the same effect as that of when the gapbetween the pair of clamp sections 14 is decreased, and an efficientlyincreased cleaving load is given to the protective coating C3 from theedge 42 (the load varies in reverse proportion to the third power of thedistance between the fulcrums). Accordingly, the unsheathed opticalfiber U′ deflects little over the second local length L2 (FIG. 7( b)).As a result, the edge 42 of the blade section 16 reliably penetratesthrough the protective coating C3 of the unsheathed optical fiber U′ atthe fiber cleaving position P, and the edge 42 bites into the claddingC2 by an amount that is necessary and sufficient. During the scribingoperation, the thin plate member 56 avoids the contact with the secondlocal length L2 of the unsheathed optical fiber U′ owing to the reliefarea 60. Despite the scribing operation is repeated, therefore, anexcess of frictional load is not exerted on the edge 42 of the bladesection 16, preventing a decrease in the life of the edge.

After the above scribing operation, the pusher section 18 is caused toswing in a direction to approach the unsheathed optical fiber U′supported by the clamp sections 14 from the initial position (FIG. 8) ina state where the blade section 16 is disposed separated away from theunsheathed fiber U on the side opposite to the initial position. Here,the swelling portion at the end of the pusher section having the pushingface 48 has been determined for its size in advance so as to passtogether with the unsheathed optical fiber U′, in a non-contactingmanner, through the relief area 60 in the thin plate member 56 supportedby the clamp sections 14. Then, at the fiber cleaving position P, thepushing face 48 exerts the pushing force f produced by, for example,hand onto the surface of the unsheathed fiber U′ on the side opposite tothe score produced by the blade section 16 in a direction nearly atright angles with the axis of the unsheathed fiber U′ at the fibercleaving position P. As a result, tensile stress generates in theunsheathed optical fiber U′ with the score as a center, and theunsheathed fiber U′ is cleaved at a desired portion to form an endsurface E (FIG. 7( c)).

The thin plate member 56 constituting the auxiliary support section 54is made of a material having a shape and a size, that are so selected asto exhibit the action of decreasing the gap between the fulcrums. Theeffect of decreasing the gap between the fulcrums is affected by apredetermined gap between the clamp sections 14, outer diameter of thecladding C2, thickness of the protective coating C3 of the unsheathedoptical fiber U′ that is to be cleaved, and the Young's modulus of theunsheathed optical fiber U′. As a material of the thin plate member 56,there can be used various materials such as metals, resins, rubbers,papers, cloths or the like that can be easily molded to assume a desiredouter shape having a desired thickness. Further, the size of the fibersupport faces 58 of the thin plate member 56 (particularly, the size ofthe unsheathed optical fiber U′ corresponding to the local length L1)can be suitably set by taking into consideration the material of thethin plate member 56 and the deflection suppress amount required for theunsheathed fiber U′. In order to avoid an undesirable deformation of thethin plate member 56, the thin plate member 56 may be locally bent ormay be locally provided with a rib or frame-like thickened portion in anarea free from the unsheathed optical fiber U′, so as to increase thestrength of the thin plate member 56. Moreover, in order to apply thehighly accurate cleaving process using the auxiliary support section 54to many kinds of optical fibers of different constitutions (outerdiameters of unsheathed fibers), it is advantageous to prepare manykinds of thin plate members 56 of various materials having variousshapes and sizes.

It is, further, desired that the holdable areas 62 of the thin platemember 56 have such sizes as will not extend beyond the elastic pieces40 mounted on the first and second clamp members 34 and 36 of the clampsections 14 in a direction at right angles with the axis of theunsheathed optical fiber U′ that is to be supported when the thin platemember 56 is at the operable position (FIG. 9). According to thisconstitution, the unsheathed optical fiber U′ and the holdable areas 62of the thin plate member 56 bite into the elastic pieces 40 of the firstand second clamp members 34 and 36, whereby the clamp surfaces 34 a and36 a of the clamp members 34 and 36 are reliably and intimatelycontacted together and, as a result, the cover section 30 is held at thepredetermined closed position relative to the base section 12.

According to the optical fiber cleaving device 10 constituted asdescribed above, it is allowed to reliably form a mirror-like endsurface E at right angles at an end of the unsheathed fiber U′ of theoptical fiber F′ with the protective coating, the optical fiber F′having the unsheathed fiber U′ of the same outer diameter as that of theunsheathed fiber U by simply placing the thin plate member 56 of theauxiliary support section 54 at the operable position without the needof changing the relative positional relationship between the clampsections 14 and the blade section 16 that has been set in advance toeffect the highly accurate cleaving process for the general opticalfibers F without the protective coating. The auxiliary support section54 is constituted by the thin plate member 56 of a simple structurewhich is inexpensive without causing such problems as complexity in thestructure of the cleaving device or an increased cost. In the thin platemember 56, particularly, it is possible to precisely determine theposition or height of the fiber support faces 58 on the base section 12by only firmly clamp the holdable areas 56 in the clamp sections 14, sothat it is possible to incorporate, in a low cost, the high-precisionauxiliary support section 54 into optical fiber cleaving devices havingconventional structures. In the fiber cleaving operation, the thin platemember 56 of the material having the shape and size that are so selectedas to exhibit the above-mentioned action of decreasing the gap betweenthe fulcrums, is held together with the unsheathed fiber U′ by the clampsections 14 to scribe the cladding C2 of the unsheathed fiber U′ to adegree necessary and sufficient by the edge 42 of the blade section 16relying upon an ordinary operation, to carry out the highly accuratecleaving operation without requiring skill of the worker. As for thewearing of the thin plate member 56, the thin plate member 56 mounted onthe cover section 30 is so constituted as can be easily replaced withoutrequiring complex maintenance operation.

The auxiliary support section 54 which is the thin plate member of theabove embodiment can have a variety of constitutions.

Referring, for example, to FIG. 10, a piece of thin plate member 68punched in a symmetrical manner from the thin plate member can behandled as a member independent from the base section 12 and the coversection 30. The diagramed thin plate member 68 includes a pair of fibersupport faces 70, a relief area 72 which is a through hole formed at thecenter between the fiber support faces 70 adjacent thereto, and a pairof holdable areas 74 formed on the outer sides of the two fiber supportfaces 70 adjacent thereto. The thin plate member 68 can be used at theabove-mentioned operable position (being supported together with theunsheathed fiber U′ by the clamp sections 14) during the step ofcleaving the optical fiber F′ with the protective coating.

Referring to FIG. 11, further, there can be employed a thin plate member82 having a pair of fiber support faces 78 formed on both sides of acentral relief area 76 adjacent thereto, and a pair of grooves 80 formedon both sides of the relief area 76 adjacent thereto at positionsdifferent from the fiber support faces 78. The thin plate member 82 isplaced at the above-mentioned operable position with its pair of grooves80 being aligned in a direction in which the blade section 16 moves andbeing disposed facing the moving passage thereof. While the unsheathedfiber is being scribed by the blade section 16, therefore, the grooves80 work to avoid the contact between the thin plate member 82 at theoperable position and the edge 42 of the blade section 16 moving nearthe fiber cleaving position P. Accordingly, even when the height of theedge 42 of the blade section 16 has been set to be higher than the clampfaces 34 a (FIG. 3) of the first clamp members 34, it is allowed toreliably avoid the contact between the thin plate member 82 and the edge42 and, hence, to prevent damage to them in advance.

As shown in FIG. 11, further, the pair of fiber support faces 78 can beso formed as to swell on the surfaces of the holdable areas 84 formed onthe outer sides thereof. According to this constitution, when the thinplate member 82 is placed at the operable position, the two fibersupport faces 78 are disposed to be lower than the clamp faces 34 a ofthe first clamp members 34 (i.e., disposed to be close to the bladesection 16). In scribing the unsheathed fiber by using the blade section16, therefore, the unsheathed optical fiber U′ extending between the twoclamp sections 14 is forcibly deflected over the local lengths L1 and L2in a direction toward the blade section 16 along the two fiber supportfaces 78. As a result, the distance is shortened between the cladding C2of the unsheathed optical fiber U′ and the edge 42 of the blade section16, and the cladding C2 can be scribed more reliably by the edge 42.Further, the size of the two fiber support faces 78 particularly, sizecorresponding to the local length L1 of the unsheathed optical fiber U′)can be shortened by an amount by which the distance is shortened betweenthe cladding C2 and the edge 42, and the size of the relief area 76(particularly, size corresponding to the local length L2 of theunsheathed optical fiber U′) can be increased.

The thin plate members 68 and 82 which are the independent members asdescribed above can, as required, be used being suitably secured to theclamp faces 36 a of the second clamp members 36 of the clamp sections 14by using double-sided adhesive tapes. In their place or in additionthereto, a thin plate member 86 independent from the base section 12 andthe cover section 30 can be provided, as shown in FIG. 12, with a pairof resilient arms 88 capable of holding the second clamp members 36 ofthe clamp sections 14. The thin plate member 86 can be detachablyattached to the pair of second clamp members 36 via the resilient arms88 so as to be disposed at the operable position (see FIG. 13).

The thin plate member 86 includes a pair of fiber support faces 90 whichare swelling, a relief area 92 which is a through hole formed at thecenter between the fiber support faces 90 adjacent thereto, a pair ofholdable areas 94 formed on the outer sides of the fiber support faces90 adjacent thereto, and a pair of grooves 96 formed on both sides ofthe relief area 92 at positions different from the fiber support faces90, and exhibits the action and effect same as those of theabove-mentioned thin plate member 82. Here, the fiber support faces 78and 90 of the swollen shape can be formed by locally increasing thethickness of the thin plate member 82 as shown in FIG. 11, or by foldingportions of the thin plate member 86 as shown in FIG. 12.

FIG. 14 illustrates further modified examples of independent thin platemembers, in which two thin plate members 102 having a fiber support face98 of a swollen shape and a flat holdable area 100, are arranged at theoperable position so as to form a relief area 104 between the two (FIGS.10( a) and 14(b)), in which a thin portion is formed at the center ofthe thin plate member 106 which, as a whole, is a flat plate to form arelief area 108 of a recessed form (FIGS. 14( c) and 14(d)), and inwhich thin portions are formed on both sides of a relief area 112 whichis a through hole formed at the center of a generally flat thin platemember 110 thereby to form a pair of grooves 114 of a recessed form(FIGS. 14( e) and 14(f)).

Among them, it is desired that the thin plate member 106 is made of aresin film or a rubber plate so as to possess a sufficient degree offlexibility in at least the thin portion forming the relief area 108.According to this constitution, the pushing force due to the pushingface 48 can be reliably transmitted to the unsheathed fiber U relyingupon the deformation of the thin portion during the unsheathed fiberpushing (cleaving) operation by the pusher section 18 in the cleavingprocess without the need of moving the thin plate member 106 from theoperable position. In carrying out the unsheathed fiber pushing(cleaving) operation, however, if it is permitted to once move the coversection 30 to the open position relative to the base section 12 in orderto separate the thin plate member away from the operable position, it isallowed in the present invention to employ even a thin plate member of aconstitution that prevents the pushing operation by the pushing face ofthe pusher section 18.

The auxiliary support section 54 made of the thin plate member can beused being mounted on the fiber holder 24 as shown in, for example, FIG.15. In the illustrated embodiment, the thin plate member 82 shown inFIG. 11 is secured at the edge of its one holdable area 84 to the edgeof the holder plate 28 of the fiber holder 24 on the side of leading outthe unsheathed fiber (FIG. 15( a)). In this constitution, the fiberholder 24 holding the optical fiber F′ (FIG. 15( b)) is mounted on thebase section 12 to place the unsheathed fiber U′ in position withrespect to the clamp sections 14 and, at the same time, the thin platemember 82 is automatically disposed at the operable position.

In the above-mentioned embodiment and modified examples thereof, theauxiliary support section 54 constituted by the thin plate member isdisposed at its operable position to be on the side opposite to the edge42 of the blade section 16 that passes through the fiber cleavingposition P with respect to the unsheathed optical fiber U′ supported bythe clamp sections 14. According to the present invention, however, itis also allowable, contrary to the above, to arrange, at its operableposition, the auxiliary support section 54 constituted by the thin platemember on the side same as the edge 42 of the blade section 16 passingthrough the fiber cleaving position P with respect to the unsheathedoptical fiber U supported by the clamp sections 14. According to thelatter constitution, when a relative positional relationship between theclamp sections 14 and the blade section 16 has been so set that theoptical fiber cleaving device 10 effects the highly accurate cleavingprocess to the optical fiber F′ with the protective coating, thedistance can be easily expanded between the unsheathed optical fibersupported by the clamp sections 14 and the edge 42 of the blade section16 at the fiber cleaving position P by placing the thin plate member ofthe auxiliary support section 54 at the operable position. By simplyplacing the thin plate member of the auxiliary support section 54 at theoperable position, therefore, a mirror-like end surface E can bereliably formed at right angles at the edge of the optical fiber Fwithout the protective coating but having the unsheathed fiber U of thesame diameter as the unsheathed fiber U′ preventing the unsheathed fiberU from being cleaved to an excess degree.

As can be implied from the above various modified examples, the opticalfiber cleaving method of the present invention is not necessarily tocleave the optical fiber by using the cleaving device equipped with theblade section and the pusher section intensively. If the optical fibercleaving method according to the present invention is described incompliance with the above first embodiment, first, there are providedthe pair of clamp sections 14 capable of supporting the unsheathedoptical fibers U, U′, the clamps 14 being so disposed as to maintain apredetermined gap between them. There is further provided the auxiliarysupport section (i.e., thin plate member 56) having a pair of fibersupport faces 58 for supporting the unsheathed optical fiber U′ incooperation with the two clamp sections 14. Next, the unsheathed opticalfiber U′ is supported on the clamp sections 14 so as to extend betweenthe clamp sections. Then, the thin plate member 56 is disposed in afixed manner relative to the clamp sections 14 such that the fibersupport faces 58 come in contact with the local lengths L1 of theunsheathed optical fiber U′ extending between the clamp sections 14. Inthis state, the surface is locally scribed at a target point in theportion of the local length L2 of the unsheathed optical fiber U′,adjacent to the local lengths L1, between the clamp sections 14 by usinga desired edge in a direction nearly at right angles with the axis ofthe unsheathed fiber U′. Finally, the pushing force is applied bydesired pushing faces onto the second local length L2 of the unsheathedoptical fiber U′ between the clamp sections 14 thereby to cleave theunsheathed fiber U′ at the desired portion.

FIG. 16 illustrates an optical fiber cleaving device 120 according to asecond embodiment of the present invention. The optical fiber cleavingdevice 120 is constituted in substantially the same manner as theoptical fiber cleaving device 10 according to the first embodimentexcept the constitution of the auxiliary support section. Therefore, thecorresponding constituent elements are denoted by common referencenumerals but their description is not repeated. In the optical fibercleaving device 120, a relative positional relationship between theclamp sections 14 and the blade section 16 has been so set in advancethat the highly accurate cleaving process can be effected for theoptical fiber F (FIG. 4( a)) without the protective coating.

The optical fiber cleaving device 120 is equipped with an auxiliarysupport section 122 movably disposed on the base section 12independently from the blade section 16 and the pusher section 18, whichis a characteristic constitution of the invention. The auxiliary supportsection 122 can be disposed on the base section 12 at the operableposition. At the operable position, the auxiliary support section 122supports the unsheathed optical fiber U′ with the protective coating C3(FIG. 4( b)) in cooperation with the clamp sections 14. The opticalfiber cleaving device 120 effects the cleaving process for theunsheathed optical fibers U, U′ of different kinds having the same outerdiameter by moving the auxiliary support section 122 between theoperable position and the inoperable position to thereby cleave theunsheathed optical fibers U, U′ highly accurately.

The auxiliary support section 122 is constituted by a piece member 124that is integrally formed in a predetermined shape. Referring to FIG.17, the piece member 124 includes a base plate 126 with a knob 126 a,and a pair of legs 128 extending nearly in parallel from the base plate126, and has, at the ends of the legs 128, fiber support faces 130locally located between the clamp sections 14 at the operable positionof the auxiliary support section 122. When the frame piece 124 is at theoperable position, the fiber support faces 130 are so disposed as tocome in contact with the pair of portions having the local length L1(see FIG. 19) of the unsheathed optical fiber U′ supported on the clampsections 14 so as to extend therebetween, the local length being locatedaway from the fiber cleaving position P.

The piece member 124 has a relief area 132 formed between the legs 128adjacent to the two fiber support faces 130. When the piece member 124is at the operable position, the relief area 132 so works as to avoidthe contact with the second local length L2 (see FIG. 19) of theunsheathed optical fiber U′, extending through the fiber cleavingposition P. The piece member 124 is so disposed that the base plate 126thereof is brought in contact with the outer surface (upper surface inFIG. 16) of the cover section 30, has its legs 128 inserted in the notch38 of the cover section 30 adjacent to the second clamp members 36 ofthe cover section 30, and is held in the notch 38 so as to slide thereindue to friction and so on. When the cover section is at the closedposition on the base section 12 with the piece member 124 being mountedon the cover section 30, the relief area 132 between the two legs 128receive the swing arm of the pusher section 18 in a non-contactingmanner.

Described below with reference to FIGS. 18 and 19 is the operation ofthe auxiliary support section 122 having the piece member 124.

First, to effect the cleaving process for the optical fiber F (FIG. 4(a)) without the protective coating, as shown in FIG. 18( a), the piecemember 124 constituting the auxiliary support section 122 is such thatthe knob 126 a is operated by, for example, hand, so that the base plate126 is placed on the cover section 30 at the inoperable positionseparated away from the cover section 30. When the cover section 30 ismoved to the closed position relative to the base section 12, the legs128 of the piece member 124 at the inoperable position have their fibersupport faces 130 at the ends disposed on the cover section 30 beinglocated away from the unsheathed optical fiber U extending between theclamp portions 14. In this state, the blade section 16 is directlyoperated on the base section 12, whereby the outer surface of thecladding of the unsheathed fiber U at the fiber cleaving position P isscribed (scored) by the edge 42 in a direction nearly at right angleswith the axis of the unsheathed fiber U (FIG. 18( b)). Then, the pushersection 18 swings so as to exert the pushing force on the unsheathedoptical fiber U due to the pushing faces 48 thereof, to cleave theunsheathed optical fiber U at the target point thereof (FIG. 3( b)). Theactions by the blade section 16 and by the pusher section 18 are thesame as those by the above-mentioned optical fiber cleaving device 10 atthe cleaving process.

When the cleaving process is to be effected for the optical fiber F′with the protective coating (FIG. 4( b)), on the other hand, the piecemember 124 is slid within the notch 38 of the cover section 30 from theinoperable position in FIG. 18 to a position where the base plate 126comes in contact with the outer surface of the cover section 30 (FIG.19( a)) before or after the unsheathed optical fiber U′ is supported bythe clamp sections 14 by disposing the cover section 30 at the closedposition on the base section 12. Then, the piece member 124 is disposedat the operable position, and the fiber support faces 130 at the ends ofthe legs 128 are brought into contact with the pair of local lengths L1,located adjacent to the clamp sections 14, of the unsheathed opticalfiber U′ extending between the clamp sections 14.

In this state, the blade section 16 is directly operated on the basesection 12 and the edge 42 is brought into contact with the surface ofthe unsheathed optical fiber U′. Then, the two fiber support faces 130of the piece member 124 work as fixed fulcrums in one direction for theunsheathed fiber U′ receiving, on the upper side, the contacting forceof the edge 42 from the lower side, effectively increasing the cleavingload exerted on the protective coating from the edge 42 and decreasingthe amount of deflection of the second local length L2 of the unsheathedfiber U′ (FIG. 19( b)). As a result, the edge 42 of the blade section 16reliably penetrates through the protective coating of the unsheathedoptical fiber U′ at the fiber cleaving position P and bites into thecladding by an amount which is necessary and sufficient. During thescribing operation, the piece member 124 is avoiding the contact withthe second local length L2 of the unsheathed optical fiber U′ owing tothe relief area 132. Even when the scribing operation is repeated,therefore, excess of frictional load is not exerted on the edge 42 ofthe blade section 16, preventing a decrease in the life of the edge.

Next, the pusher section 18 swings, the pushing faces 48 thereof exertpushing force on the unsheathed optical fiber U to cleave it at a targetpoint (see FIG. 7( c)). The actions by the blade section 16 and thepusher section 18 are the same as those at the cleaving process by usingthe above-mentioned optical fiber cleaving device 10.

The piece member 124 constituting the auxiliary support section 122 ismade of a material that has been selected in advance in a shape and sizeso as to exhibit the action for decreasing the required distance betweenthe fulcrums. As the material of the piece member 124, there can be usedvarious materials such as a metal, a resin or the like having a rigidityfor maintaining at least the shape of the fiber support faces 130 duringthe cleaving process. The size of the fiber support faces 130 of thepiece member 124 particularly, the size corresponding to a portion ofthe local length L1 of the unsheathed optical fiber U′) is suitably setby taking into consideration the amount of deflection required for theunsheathed fiber U′. The fiber support faces 130 of the piece member 124can further be so constituted as to support the portions of a desiredlocal length of the unsheathed fiber U′ at positions slightly separatedaway from the clamp sections 14. It is advantageous to provide manykinds of piece members 124 of various materials having various shapesand sizes to effect the highly accurate cleaving process by using theauxiliary support section 122 for many kinds of optical fibers havingdifferent constitutions (outer diameters of the unsheathed fibers,etc.).

It can be comprehended that the action and effect same as those of theabove-mentioned optical fiber cleaving device 10 can be obtained even byusing the optical fiber cleaving device 120 constituted as describedabove. In particular, the optical fiber cleaving device 120 employs theauxiliary support section 122 constituted by the piece member 124 whichhas rigidity by itself, making maintenance further easy, such aspreserving the auxiliary support section 122 and handling as compared tothe auxiliary support section 54 made of the thin plate member 56described above. In place of the illustrated structure, the piece member124 may be arranged to be rotatable on the cover section 30.

FIG. 20 illustrates an optical fiber cleaving device 140 according to athird embodiment of the present invention. The optical fiber cleavingdevice 140 is constituted in substantially the same manner as theoptical fiber cleaving device 10 according to the first embodimentexcept the constitution of the auxiliary support section. Therefore, thecorresponding constituent elements are denoted by common referencenumerals but their description is not repeated. In the optical fibercleaving device 140, a relative positional relationship between theclamp sections 14 and the blade section 16 has been so set in advancethat the highly accurate cleaving process can be effected for theoptical fiber F (FIG. 4( a)) without the protective coating.

The optical fiber cleaving device 140 is equipped with an auxiliarysupport section 142 movably disposed on the base section 12independently from the blade section 16 and the pusher section 18, whichis a characteristic constitution of the invention. The auxiliary supportsection 142 can be disposed on the base section 12 at the operableposition. At the operable position, the auxiliary support section 142supports the unsheathed optical fiber U′ with the protective coating C3(FIG. 4( b)) in cooperation with the clamp sections 14. The opticalfiber cleaving device 140 effects the cleaving process for theunsheathed optical fibers U, U′ of different kinds having the same outerdiameter by moving the auxiliary support section 142 between theoperable position and the inoperable position to thereby cleave theunsheathed optical fibers U, U′ highly accurately.

Referring to FIG. 21, the auxiliary support section 142 is constitutedby a pair of disc members 144 each having a rotary axis 144 a. The discmembers 144 are rotatably mounted on the cover section 30 via pivotshafts that are not shown with the rotary axis 144 a as a center. Thedisc members 144 are disposed adjacent to the second clamp members 36 inthe notch 38 of the cover section 30. Referring to FIG. 22, each discmember 144 has a plurality of sectorial areas 146 divided into sectorswith the rotary axis 144 a as a center. The sectorial areas 146 havedifferent thicknesses (sizes in the axial direction), and have nearlyflat fiber support faces 148 of different sizes in the axial directionon the outer end surfaces in the radial direction of the sectorial areas146 (on the outer peripheral surfaces of the disc member 144). The fibersupport faces 148 are disposed at positions of an equal distance fromthe rotary axis 144 a at the central portions in the circumferentialdirection thereof. Further, an inoperable face 150 is formed in theouter end surface in the radial direction of a desired sectorial area146 (thinnest sectorial region 146 in the drawing) being deviated at aposition closer to the center of rotation (i.e., axis 144 a) from thefiber support faces 148.

When the disc members 144 are at the operable positions, the fibersupport faces 148 of the disc members 144 are disposed to come incontact with the pair of local lengths L1 (see FIG. 23) of theunsheathed optical fiber U′ supported to extend between the clampsections 14, the local length being located away from the fiber cleavingposition P. When the disk members 144 are at the operable positions,further, the space between the disc members 144 mounted on the coversection 30 work as relief area for avoiding the contact with the secondlocal length L2 (see FIG. 23) of the unsheathed optical fiber U′ thatextends passing through the fiber cleaving position P. Due to thefriction to the profile face of the notch 38 on the cover section 30,the disc members 144 are held at such rotational positions that desiredfiber support faces 148 are neighbored to the clamp faces 36 a of thesecond clamp members 36 in flush with each other. When the cover section30 is at the closed position on the base section 12, the space betweenthe disc members 144 work to receive the swing arm of the pusher section18 in a non-contacting manner.

The operation of the auxiliary support section 122 having the discmember 144 will now be described with reference to FIG. 23.

First, when the cleaving process is to be effected for the optical fiberF (FIG. 4( a)) without the protective coating, the disc members 144 areturned by, for example, hand as shown in FIG. 23( a), whereby theinoperable faces 150 are brought to the inoperable positions adjacent tothe clamp faces 36 a of the second clamp members 36 on the cover section30. When the cover section 30 is moved to the closed position relativeto the base section 12, the inoperable faces 150 of the disk members 144at the inoperable positions are disposed to be separated away from theunsheathed optical fiber U extending between the clamp sections 14. Inthis state, the blade section 16 is directly operated on the basesection 12, whereby the outer surface of the cladding of the unsheathedfiber U at the fiber cleaving position P is scribed (i.e., scored) bythe edge 42 in a direction nearly at right angles with the axis of theunsheathed fiber U. Then, the pusher section 18 is operated to swing,whereby a pushing force is exerted on the unsheathed optical fiber Ufrom the pushing faces 48, and the target point is cleaved (see FIG. 3(b)). The actions of the blade section 16 and the pusher section 18 arethe same as those obtained in the cleaving process by using the opticalfiber cleaving device 10 described above.

When the cleaving process is to be effected for the optical fiber F′with the protective coating FIG. 4( b)), on the other hand, the discmembers 144 are turned within the notch 38 of the cover section 30 fromthe inoperable position in FIG. 23( a) to the positions where thedesired fiber support faces 148 are neighbored to the clamp surfaces 36a of the second clamp members 36 (FIG. 23( b)) before or after theunsheathed optical fiber U′ is supported by the clamp sections 14 bydisposing the closure section 30 at the closed position on the basesection 12. Then, the disc members 144 are disposed at the operablepositions, and the desired fiber support faces 148 are brought intocontact with the pair of local lengths L1, adjacent to the clampsections 14, of the unsheathed optical fiber U′ extending between theclamp sections 14.

In this state, the blade section 16 is directly operated on the basesection 12 and the edge 42 is brought into contact with the surface ofthe unsheathed optical fiber U′. Then, the fiber support faces 148 ofthe disc members 144 work as fixed fulcrums in one direction for theunsheathed fiber U′ receiving, on the upper side, the contacting forceof the edge 42 from the lower side, effectively increasing the cleavingload exerted on the protective coating from the edge 42 and decreasingthe amount of deflection of the second local length L2 of the unsheathedfiber U′ (FIG. 23( b)). As a result, the edge 42 of the blade section 16reliably penetrates through the protective coating of the unsheathedoptical fiber U′ at the fiber cleaving position P and bites into thecladding by an amount which is necessary and sufficient. During thescribing operation, the space between the disc members 144 serves as arelief area to avoid the contact with the second local length L2 of theunsheathed optical fiber U′. Even when the scribing operation isrepeated, therefore, excess of frictional load is not exerted on theedge 42 of the blade section 16, preventing a decrease in the life ofthe edge.

Next, the pusher section 18 swings, the pushing faces 48 thereof exertpushing force on the unsheathed optical fiber U to cleave it at a targetpoint (see FIG. 7( c)). The actions by the blade section 16 and thepusher section 18 are the same as those of the cleaving process by usingthe above-mentioned optical fiber cleaving device 10.

The disc members 144 constituting the auxiliary support section 122 aremade of a material that has been selected in advance in a shape and sizeso as to exhibit the action for decreasing the required distance betweenthe fulcrums. As the material of the disc members 144, there can be usedvarious materials such as a metal, a resin or the like having a rigidityfor maintaining at least the shape of the fiber support faces 148 duringthe cleaving process. The size of the fiber support faces 148 of thedisc members 144 (particularly, the size corresponding to a portion ofthe local length L1 of the unsheathed optical fiber U′) can be suitablyset to a variety of sizes by taking into consideration the amount ofdeflection required for many kinds of the unsheathed fibers U′ havingdifferent constitutions (outer diameters of the unsheathed fibers).

It can be comprehended that the action and effect same as those of theoptical fiber cleaving device 10 can be obtained even by using theoptical fiber cleaving device 140 constituted as described above. Inparticular, the optical fiber cleaving device 140 employs the auxiliarysupport section 142 constituted by the disc members 144 having rigidityby itself, offering such advantages as easier maintenance such aspreservation of auxiliary support section 142 and handling as comparedto the auxiliary support section 54 constituted by the thin plate member56. By simply providing the disc members 144 of one kind only, further,there is obtained such an advantage that the highly accurate cleavingprocess can be effected by using the auxiliary support section 142 formany kinds of optical fibers having different constitutions (outerdiameters of the unsheathed fibers, etc.).

In the foregoing were described preferred embodiments of the presentinvention in connection with the optical fibers F, F′ having differentfiber structures depending upon the presence or absence of protectivecoating. However, it can be comprehended that the present invention isin no way limited to the above applications but can further be appliedeven when it is attempted to cleave, by using a single kind of cleavingdevice, the optical fibers having different fiber structures using coresand claddings of different materials (such as quartz core/quartzcladding, quartz core/resin cladding, multi-component glasscore/multi-component glass cladding, etc.).

EXAMPLES Experiment 1

An experiment was conducted for cleaving an optical fiber F′ with aprotective coating by using the optical fiber cleaving device 10 shownin FIG. 1 under the conditions most suited for cleaving the opticalfiber F without the protective coating while using, as the auxiliarysupport section 54, the thin plate member 56 of a brass having athickness of 0.08 mm. The thin plate members 56 were provided in fivekinds having relief areas 60 of sizes (sizes corresponding to L2 in FIG.7) of 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, and were successively exchanged tocarry out the step of cleaving. The relief areas 60 of these thin platemembers 56 were of such sizes (particularly, 1 to 4 mm) that did notpermit the passage of the pushing faces 48 of the pushing section 18.After the scribing operation by the blade section 16, therefore, thecover section 30 was moved to the open position, and the thin platemember 56 was disposed at the inoperable position. The object opticalfiber F′ was a single-mode optical fiber (manufactured by 3M Co.) havinga quartz cladding diameter of 100 μm and a mode field diameter of 9.2μm, having a protective coating C3 of a thickness of 12.5 μm formed onthe surface of the cladding C2 and an outer diameter of the unsheathedfiber U′ of 125 μm in compliance with the International standard value.The sheath S was formed of an ultraviolet-ray curable resin, and theouter diameter of the product was 250 ml.

In the above experiment, when the thin plate members 56 having therelief areas 60 of 1 mm to 4 mm were disposed at the operable position,the unsheathed fiber of the optical fiber F′ with the protective coatingcould be cleaved highly accurately. When the thin plate member 56 havingthe relief area 60 of 5 mm was disposed at the operable position andwhen the thin plate member 56 was not disposed at the operable position,the unsheathed fiber U′ of the optical fiber F′ with the protectivecoating could not be cleaved.

Experiment 2

An experiment was conducted for cleaving an optical fiber F′ with aprotective coating by using the optical fiber cleaving device 10 shownin FIG. 1 under the conditions most suited for cleaving the opticalfiber F without the protective coating while using, as the auxiliarysupport section 54, the thin plate member 82 of a brass having athickness of 0.08 mm. The thin plate member 82 possessed a relief area76 of a size (size corresponding to L2 in FIG. 7) of 5 mm. A brass foilof a thickness of 0.03 mm was stuck onto both sides of the relief area76 to form fiber support faces 78 of a swollen shape. The optical fibersF′ being treated were the same as those of Experiment 1.

In the above experiment, the cleaving process were effected for fouroptical fibers F′ with the protective coating. The unsheathed opticalfibers U′ could be highly accurately cleaved by any cleaving process.The inclinations of end surfaces E (angles with respect to a plane atright angles with the axis) formed on the unsheathed fibers U′ were 0.8°on the average and were 1.5° at the greatest.

According to the present invention as will be apparent from theforegoing description, there is provided an optical fiber cleavingdevice for cleaving an unsheathed optical fiber extending between theclamp sections by scribing the surface thereof with the edge of theblade section and then pushing it, wherein scores are easily andreliably imparted to the surfaces of the unsheathed fibers to a degreenecessary and sufficient for forming mirror-like end surfaces at rightangles at the ends of the optical fibers having different unsheathedfiber structures without changing the relative positional relationshipbetween the clamp sections and the blade section, excluding theprobability of a decrease in the life of the edge of the blade sectionand offering general applicability.

According to the present invention, there is further provided an opticalfiber cleaving method of cleaving an unsheathed optical fiber extendingbetween the clamp sections by scribing the surface thereof and thenpushing it, wherein scores are easily and reliably imparted to thesurfaces of the unsheathed fibers to a degree necessary and sufficientfor forming mirror-like end surfaces at right angles at the ends of theoptical fibers having different unsheathed fiber structures withoutchanging the gap between the clamp sections.

1. An optical fiber cleaving device comprising a base section, a pair ofclamp sections provided on said base section and spaced at apredetermined distance from each other for supporting an unsheathedoptical fiber extending therebetween, a blade section provided movablyrelative to said base section and including an edge capable of beingdisposed at a fiber cleaving position defined between said clampsections, and a pusher section provided movably relative to said basesection independently of said blade section and including a pushing facecapable of being disposed at said fiber cleaving position, wherein: saidoptical fiber cleaving device comprises an auxiliary support sectionpivotably disposed on one of the base and a cover section, and providedseparate from the clamp sections and movable relative to said basesection independently of said blade section and said pusher section, andcapable of being disposed at an operable position for supporting anunsheathed optical fiber in cooperation with said clamp sections; andsaid auxiliary support section includes first and second auxiliarysupport sections provided on both sides of the blade section when in theoperable position, said first and second auxiliary support sectionsincludes a fiber support face locally located between said clampsections separately from fiber clamping surface of the fiber clampingsections at said operable position, said fiber support face being soarranged as to come in contact with a local length of an unsheathedoptical fiber extending between said clamp sections, the local lengthbeing located away from said fiber cleaving position.
 2. An opticalfiber cleaving device according to claim 1, wherein said auxiliarysupport section comprises a thin plate member including said fibersupport face, a relief area formed adjacent to said fiber support faceso as to be free of contact with a second local length of saidunsheathed optical fiber located at said fiber cleaving position, andholdable areas formed adjacent to both of said first and second fibersupport faces so as to be clamped by clamping surfaces of said clampsections together with said unsheathed optical fiber.
 3. A method forcleaving optical fibers, wherein the method comprises: providing a pairof clamp sections capable of respectively supporting an unsheathedoptical fiber, and spacing said clamp sections at a predetermineddistance from each other; providing an auxiliary support memberpivotably disposed on one of a base and a cover section, and separatefrom and movable relative to the clamp sections including a fibersupport face capable of supporting an unsheathed optical fiber incooperation with said clamp sections; supporting an unsheathed opticalfiber on said clamp sections so as to extend between said clampsections; securely arranging said auxiliary support member relative tosaid clamp sections in a manner that said fiber support face come incontact with a first local length of said unsheathed optical fiberextending between said clamp sections; locally scribing a surface of atarget point in a second local length of said unsheathed optical fiber,adjacent to said first local length, between said clamp sections in adirection generally perpendicular to an axis of said unsheathed opticalfiber; and applying a pushing force to said second local length of saidunsheathed optical fiber in a radial direction between said clampsections, so as to cleave said unsheathed optical fiber at said targetpoint.